热固耦合作用下的套管-水泥环-地层多层组合系统应力分析

摘要

考虑非均匀地应力、内压和地层高温对高温高压井套管-水泥环-地层多层组合系统的作用,应用弹性力学理论,结合边界条件、接触条件和连续条件,获得热固耦合作用下套管-水泥环-地层多层组合系统应力分布的解析解.讨论水泥环厚度、弹性模量、泊松比、地层温度、套管-水泥环层数对最内层套管内壁Mises应力分布规律的影响.研究结果表明:上述因素对最内层套管内壁Mises应力的分布均有影响;对比套管-水泥环-地层的单层和多层组合系统,多层组合系统的最内层套管内壁的Mises应力较单层系统明显降低,这说明多层组合系统具有重要的工程价值.%According to elastic mechanics, analytical solution of the equations under the action of thermo-structural coupling was obtained by considering contact, continuity and boundary conditions in the multilayer composite system of casing-cement sheath-formation in HPHT production well. The multilayer composite system was subjected to non-uniform in-situ stress, uniform inner pressure and temperature pressure. The influences of cement thickness, cement elastic modulus, cement Poisson's ratio, formation temperature and layer number of casing-cement sheath on Mises stress distribution of the inside wall of innermost layer casing were discussed. The results show that all the above factors have great influences on the Mises stress distribution. Comparing monolayer and multilayer casing-cement sheath- formation system of casing-cement sheath-formation, the Mises stress distribution of the inside wall of innermost layer casing in multilayer casing-cement sheath-formation system is distinctly decreased, and so the multilayer casing-cement sheath-formation system has an important engineering value to ensure the safety of casing strength during service.